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DA0-001 · Question #254

A market research firm has data sets based on surveys. A data analyst wants to know if any outliers are present in a data set. Which of the following would be the BEST method to examine the…

The correct answer is C. Build a scatter plot of each variable and look for observations that are out of place. To visually identify outliers in numerical variables within a dataset, a scatter plot is the most effective method as it directly displays individual data points and makes unusual observations stand out.

Visualization

Question

A market research firm has data sets based on surveys. A data analyst wants to know if any outliers are present in a data set. Which of the following would be the BEST method to examine the numerical variables in the data set visually and find any outliers?

Options

  • APlot the linear correlations between each pair of variables and look for unusual relationships
  • BCreate a bar chart for each variable and look for any distributions that are unusual.
  • CBuild a scatter plot of each variable and look for observations that are out of place.
  • DOrder each variable in a spreadsheet from lowest to highest and look for unusual numbers at the

How the community answered

(59 responses)
  • A
    7% (4)
  • B
    12% (7)
  • C
    78% (46)
  • D
    3% (2)

Why each option

To visually identify outliers in numerical variables within a dataset, a scatter plot is the most effective method as it directly displays individual data points and makes unusual observations stand out.

APlot the linear correlations between each pair of variables and look for unusual relationships

Plotting linear correlations shows the relationship between variables, not individual outliers within a single variable or across a dataset directly.

BCreate a bar chart for each variable and look for any distributions that are unusual.

Bar charts are typically used for categorical data or showing frequencies, and while they can show unusual distributions, they are not the best for precisely identifying individual numerical outliers.

CBuild a scatter plot of each variable and look for observations that are out of place.Correct

A scatter plot shows individual data points on a two-dimensional graph, allowing an analyst to easily spot observations that lie far away from the general cluster of points, which are indicative of outliers. This visual representation helps identify extreme values that deviate significantly from the rest of the data.

DOrder each variable in a spreadsheet from lowest to highest and look for unusual numbers at the

Ordering variables in a spreadsheet is a manual, non-visual method that makes identifying outliers cumbersome and less intuitive than a graphical representation.

Concept tested: Visualizing numerical data outliers

Topics

#Outlier detection#Data visualization#Numerical data#Exploratory data analysis

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